John Costello took his puppy, Rosie, for a walk near a pond in Canton, Massachusetts, on Sunday. The 12-week-old German shepherd excitedly jumped in the car as Costello started it up. Rosie jumped into the front seat, knocked the gear shift into forward gear, and then fell onto the gas pedal. The car sped off -straight into the pond. As the car sank, the puppy jumped back into the back seat, which caused a few moments panic.

"When the car first went into the water, I jumped out to grab the dog and she jumped into the back seat," Costello said.

And that's when Eric Hermann, who was working nearby, rushed to help.

"It was about 30 feet out the car," Hermann said. "Puppy was scared and ran to the back seat. The front door was open, [we were] trying to get him out the front door, coax him."

Hermann, Costello and another man all swam to save Rosie.

"I just leaped in and grabbed the dog and pulled her out and we both fell back into the water," said Costello.